Position control apparatus for steering column

Abstract

A position control apparatus for an adjustable motor vehicle steering column including a clamp having a first jaw element and a second jaw element shiftable axially relative to each other, a control lever pivotable through an angular stroke in opening and closing directions, a primary cam means for converting pivotal movement of the control lever in the closing direction to a uniform axial stroke of the first jaw element relative to the second jaw element, and a secondary cam means for converting pivotal movement of the control lever in the opening direction to a snap-action axial stroke of the first jaw element relative to the second jaw element at a terminal end of the angular stroke of the control lever in the opening direction.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A position control apparatus for a motor vehicle steering column having a mast jacket movable in the direction of a longitudinal centerline of said steering column through a range of adjusted positions comprising: a stationary bracket having a stationary leg in a vertical plane adjacent said mast jacket,   a movable bracket attached to said mast jacket having a movable leg in a vertical plane juxtaposed said stationary leg and movable with said mast jacket relative to said stationary leg,   a clamp means on said stationary bracket operative to prevent movement of said mast jacket through said range of adjusted positions when said clamp means is closed and to permit movement of said mast jacket through said range of adjusted positions when said clamp means is open including a first jaw element on a first side of said movable leg and a second jaw element on an opposite second side of said juxtaposed stationary leg,   a control lever pivotable through an angular stroke in an opening direction between an up position and a down position and in an opposite closing direction between said down position and said up position,   a primary cam means connecting said control lever and said first jaw element operative to close said clamp means by moving said first jaw element through an axial stroke toward said second jaw element concurrently and uniformly with pivotal movement of said control lever through said angular stroke thereof in said closing direction, and   a secondary cam means connecting said control lever and said first jaw element operative to open said clamp means by moving said first jaw element through said axial stroke away from said second jaw element in snap-action fashion at a terminal end said pivotal movement of said control lever through said angular stroke thereof in said opening direction so that said clamp means is not open and said mast jacket is not movable relative to said stationary bracket until said terminal end of said pivotal movement of said control lever in said opening direction.   
     
     
       2. The position control apparatus recited in claim 1 further comprising: a spring between said first jaw element and said movable leg biasing said first jaw element away from said second jaw element.   
     
     
       3. The position control apparatus recited in claim 2 wherein said primary cam means includes: a control shaft rotatable about a lateral centerline perpendicular to each of said movable leg and said juxtaposed stationary leg,   a first tubular barrel rotatable as a unit with said control shaft about said lateral centerline,   a second tubular barrel having said first jaw element defined on a first annular end thereof facing said movable leg rotatably journaled on said control shaft and restrained against rotation about said lateral centerline,   a primary cam on an annular end of said first tubular barrel, and   a primary cam follower on a second annular end of said second tubular barrel facing said annular end on said first tubular barrel engageable on said primary cam.   
     
     
       4. The position control apparatus recited in claim 3 wherein said secondary cam means includes: a secondary cam on said first tubular barrel including a circumferential groove in an outer cylindrical wall of said first tubular barrel in a plane perpendicular to said lateral centerline and a ramp at an end of said circumferential groove tipped back from said plane perpendicular to said longitudinal centerline and extending from a bottom of said groove to said outer cylindrical wall of said first tubular barrel,   a resilient secondary cam follower on said second tubular barrel flexible perpendicular to said lateral centerline, and   a finger on said secondary cam follower resiliently biased thereby toward said first tubular barrel so that said finger seats in said circumferential groove during pivotal movement of said control lever through said angular stroke thereof in said opening direction and is guided by said ramp onto said outer cylindrical wall of said first tubular barrel at said terminal end of said angular stroke of said control lever in said opening direction.   
     
     
       5. The position control apparatus recited in claim 4 further comprising: a plurality of vertical spline teeth on said first annular end of said second tubular barrel, and   a plurality of vertical spline teeth on said movable leg meshing with said vertical spline teeth on said second tubular barrel when said clamp means is closed and separated from said vertical spline teeth on said second tubular barrel when said clamp means is open.